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In Vivo Mapping of Cortical Columnar Networks in the Monkey with Focal Electrical and Optical Stimulation.

Roe AW, Chernov MM, Friedman RM, Chen G - Front Neuroanat (2015)

Bottom Line: However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns.These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns.Such functionally specific network data can provide accurate views of brain network topology.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China.

ABSTRACT
There are currently largescale efforts to understand the brain as a connection machine. However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. Here, we review development and application of focal electrical and optical stimulation methods combined with optical imaging and fMRI mapping in the non-human primate. These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns. Such functionally specific network data can provide accurate views of brain network topology.

No MeSH data available.


Related in: MedlinePlus

Optical imaging of focal electrical stimulation in squirrel monkey somatosensory cortex. (A) Stimulation at 0 s (black), 50 ms (orange), 100 ms (gray), and 250 ms (blue) at 150 μA. Y axis: reflectance change dR/R. (B) Optical reflectance change increases with stimulus duration (measured at site of stimulation). (C) Optical image of local functional connectivity (from Brock et al., 2013) appears similar to (D) patches of anatomical label following focal (250 μm sized) injection (asterisk) of BDA tracer (adapted from Negyessy et al., 2013). (C,D) are from different animals. Scale bar for (C,D): 1 mm.
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Figure 3: Optical imaging of focal electrical stimulation in squirrel monkey somatosensory cortex. (A) Stimulation at 0 s (black), 50 ms (orange), 100 ms (gray), and 250 ms (blue) at 150 μA. Y axis: reflectance change dR/R. (B) Optical reflectance change increases with stimulus duration (measured at site of stimulation). (C) Optical image of local functional connectivity (from Brock et al., 2013) appears similar to (D) patches of anatomical label following focal (250 μm sized) injection (asterisk) of BDA tracer (adapted from Negyessy et al., 2013). (C,D) are from different animals. Scale bar for (C,D): 1 mm.

Mentions: This finding by Histed et al. (2009) suggested the feasibility of using electrical microstimulation to map local columnar networks. Encouraged by this study, we attempted functional mapping with electrical microstimulation in monkey somatosensory cortex. As electrical stimulation can produce either excitatory or suppressive effects depending on the stimulation intensity, it was vitally important to characterize stimulus amplitudes by systematically characterizing the stimulation parameter space (e.g., intensity, duration, laminar location, cf. Tehovnik et al., 2004, 2006, 2009). Using trains of biphasic pulses (typically 200 Hz, 0.4 ms pulse duration), and varying intensity by testing different current amplitudes (10–300 μA) and pulse numbers (1, 13, 26, 63 pulses, resulting in total train durations of 0.4, 50, 100, 250 ms), we examined the effect of stimulation intensity on neuronal firing and hemodynamic signal as measured with intrinsic signal optical imaging. With chosen electrical stimulation parameters (25 μA, 250 Hz, 100 ms), the imaged hemodynamic response to electrical stimulation mimicked that of tactile stimulation (Figure 3C); both revealed a focal 1 mm activation site consistent with a single digit representation. Increasing intensity of stimulation [either current amplitude (Figure 3A) or number of pulses, (Figure 3B)] led to increasing magnitudes of imaged reflectance change. Importantly, stimulation (e.g., 200 μA for 250 ms) elicited not only a focal activation at the site of stimulation but other focal activations within 1–2 mm of the stimulated site (Figure 3C). This activation pattern is very similar in appearance to typical intra-areal columnar networks revealed by anatomical tracer studies (Figures 1 and 3D). Direct confirmation of this anatomical correspondence is currently in progress.


In Vivo Mapping of Cortical Columnar Networks in the Monkey with Focal Electrical and Optical Stimulation.

Roe AW, Chernov MM, Friedman RM, Chen G - Front Neuroanat (2015)

Optical imaging of focal electrical stimulation in squirrel monkey somatosensory cortex. (A) Stimulation at 0 s (black), 50 ms (orange), 100 ms (gray), and 250 ms (blue) at 150 μA. Y axis: reflectance change dR/R. (B) Optical reflectance change increases with stimulus duration (measured at site of stimulation). (C) Optical image of local functional connectivity (from Brock et al., 2013) appears similar to (D) patches of anatomical label following focal (250 μm sized) injection (asterisk) of BDA tracer (adapted from Negyessy et al., 2013). (C,D) are from different animals. Scale bar for (C,D): 1 mm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644798&req=5

Figure 3: Optical imaging of focal electrical stimulation in squirrel monkey somatosensory cortex. (A) Stimulation at 0 s (black), 50 ms (orange), 100 ms (gray), and 250 ms (blue) at 150 μA. Y axis: reflectance change dR/R. (B) Optical reflectance change increases with stimulus duration (measured at site of stimulation). (C) Optical image of local functional connectivity (from Brock et al., 2013) appears similar to (D) patches of anatomical label following focal (250 μm sized) injection (asterisk) of BDA tracer (adapted from Negyessy et al., 2013). (C,D) are from different animals. Scale bar for (C,D): 1 mm.
Mentions: This finding by Histed et al. (2009) suggested the feasibility of using electrical microstimulation to map local columnar networks. Encouraged by this study, we attempted functional mapping with electrical microstimulation in monkey somatosensory cortex. As electrical stimulation can produce either excitatory or suppressive effects depending on the stimulation intensity, it was vitally important to characterize stimulus amplitudes by systematically characterizing the stimulation parameter space (e.g., intensity, duration, laminar location, cf. Tehovnik et al., 2004, 2006, 2009). Using trains of biphasic pulses (typically 200 Hz, 0.4 ms pulse duration), and varying intensity by testing different current amplitudes (10–300 μA) and pulse numbers (1, 13, 26, 63 pulses, resulting in total train durations of 0.4, 50, 100, 250 ms), we examined the effect of stimulation intensity on neuronal firing and hemodynamic signal as measured with intrinsic signal optical imaging. With chosen electrical stimulation parameters (25 μA, 250 Hz, 100 ms), the imaged hemodynamic response to electrical stimulation mimicked that of tactile stimulation (Figure 3C); both revealed a focal 1 mm activation site consistent with a single digit representation. Increasing intensity of stimulation [either current amplitude (Figure 3A) or number of pulses, (Figure 3B)] led to increasing magnitudes of imaged reflectance change. Importantly, stimulation (e.g., 200 μA for 250 ms) elicited not only a focal activation at the site of stimulation but other focal activations within 1–2 mm of the stimulated site (Figure 3C). This activation pattern is very similar in appearance to typical intra-areal columnar networks revealed by anatomical tracer studies (Figures 1 and 3D). Direct confirmation of this anatomical correspondence is currently in progress.

Bottom Line: However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns.These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns.Such functionally specific network data can provide accurate views of brain network topology.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China.

ABSTRACT
There are currently largescale efforts to understand the brain as a connection machine. However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. Here, we review development and application of focal electrical and optical stimulation methods combined with optical imaging and fMRI mapping in the non-human primate. These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns. Such functionally specific network data can provide accurate views of brain network topology.

No MeSH data available.


Related in: MedlinePlus